It is known to select, as anions, in catalysts for polyketone polymer production which are formed from a Group VIII metal, such as palladium, and a bidentate ligand containing a Group V or VI heteroatom, such as phosphorus, coordinating, acidic species, such as those formed from (a) a 2:1 reaction mixture of a substituted salicylic acid and boric acid (U.S. Pat. No. 5,187,258 to K. G. Smith), (b) tetrafluoroboric acid (U.S. Pat. Nos. 5,216,120 to E. Drent et al. and 5,243,026 to P. A. Gautier et al.), and (c) boron trifluoride diethyl ether etherate (U.S. Pat. No. 5,245,123 to E. Drent et. al.). The use of catalysts of this type, which leave acidic catalyst residues in the polyketone product or will form acidic species in the polymer during its thermal decomposition, are less than fully desired for use especially when the polyketone is one made from carbon monoxide and ethylene and is intended for use in environments where good temperature stability is desired.
More recent U.S. Pat. No. 5,352,767 to J. C. W. Chien illustrates the use of non-coordinating tetrasubstituted monoboron anions, such as boron tetraphenyl and boron tetra(pentafluorophenyl) in the polymerization of polyketone polymers containing an .alpha.-olefin containing no less than three carbon atoms. This patent teaches away from the use of ethylene as a comonomer for the polymerization reaction (See, for example, Col. 6, lines 46-49 and Col. 7, lines 4-15) even though it discloses use of catalyst systems which can be considered to be non-acidic.
European Pat. Publication No. 619,335 to BP Chemicals Ltd. contains a disclosure of using certain boron hydrocarbyl compounds as anions in catalysts for the synthesis of a polyketone polymer. The main thrust of this patent disclosure is the use of Lewis acidic, trisubstituted boron compounds of the formula BXYZ, where at least one of X, Y, or Z is a monovalent hydrocarbyl group. This patent contains an isolated, inconsistent mention of certain tetrasubstituted boron species at page 3, lines 48-53 without any other disclosure indicating that such species, which would be non-acidic, as defined hereinbelow, rather than acidic, were ever used to make polyketone polymers. The disclosure of these tetrasubstituted boron species is inconsistent with the main thrust of the disclosure of using Lewis acid species (e.g., claim 2).